Assuming you and a stranger have never met before, next second, the stranger uses the "loving" sign to you? That seems illogical.
Personally, I always believed that Rinoa was only pointing up at the sky/comet because she and Squall had both seen it, but assuming your TC/R=U theory is correct and Rinoa was trying to make Squall her knight, it wouldn't be illogical because Rinoa would already be in love with Squall and she would know that Squall would be where he was. And Squalls head tilt would be a confused head tilt as he would have no recollection of any prior meetings. And it would also explain why Rinoa knows the dance off by heart and she's not even a SeeD!!!

Hope that makes sense!